Many beginners doesn't know about that and without considering to learn about trading, they enter to the market and buy a random coins based on what they read from their social media page. That makes them lose their money and that happens over and over if they don't realize and understand that.
A good teacher can only be a practicing trader who already earns money in trading (theoretical knowledge alone will not bring results), but I doubt that such a person will want to spend his time teaching someone else, and if he does it for money, then his lessons will be very expensive, which will be too expensive for a beginner trader to afford, but most likely it will still cost him less than when he learns from his mistakes on his own.
It is quite possible that beginners will buy coins based on someone's recommendations, because choosing something yourself when you are just starting out is very difficult (an exception may be bitcoin). And they will buy at random, or based on the news, and this approach is often unprofitable because the market is constantly manipulated...